Abstract
Advanced breast cancer is known to be highly evasive to conventional therapeutic regimes with a 5-year survival rate of less than 30% compared to over 90% for early stages. Although several new approaches are being explored to improve the survival outcome, there is still some room for equipping existing drugs such as lapatinib (LAPA) and doxorubicin (DOX) to fight the systemic disease. LAPA is associated with poorer clinical outcomes in HER2-negative patients. However its ability to also target EGFR has warranted its use in recent clinical trials. Nevertheless, the drug is poorly absorbed post oral administration and possess low aqueous solubility. DOX on the other hand is avoided in vulnerable patients in advanced stages due to its pronounced off-target toxicity. To overcome the pitfalls of the drugs, we have fabricated a nanomedicine co-loaded with LAPA & DOX and stabilized with glycol chitosan, a biocompatible polyelectrolyte. With a loading content of ~ 11.5% and ~ 15% respectively, LAPA and DOX in a single nanomedicine showed synergistic action against triple-negative breast cancer cells in comparison to physically mixed free drugs. The nanomedicine showed a time-dependent association with cancer cells thereon inducing apoptosis leading to ~ 80% cell death. The nanomedicine was found to be acutely safe in healthy Balb/c mice and could negate DOX-induced cardio toxicity. The combination nanomedicine significantly inhibited both the primary 4T1 breast tumor and its spread to the lung, liver, heart, and kidney compared to pristine drug controls. These preliminary data indicate bright prospects for the nanomedicine to be effective against metastatic breast cancer.